Observations

Description

Valves are lanceolate with subcapitate to capitate apices. The valves are often slightly bent in valvar plane about the apical axis and about the median transapical plane. The raphe is almost straight. External terminal raphe fissures are strongly curved. The raphe slits are slightly shorter and the distance between central raphe endings is greater on the convex valve than on the concave valve. Striae are radiate throughout most of the valve, but become parallel or slightly convergent near the poles, 38-42 in 10 mm. Areolae are small, round, externally covered by hymens. Axial area is large, rhomboid, continuous with central area, which sometimes possesses a few isolated areolae.

Valves are lanceolate with subcapitate to capitate apices. The raphe slits are slightly shorter and the distance between central raphe endings is greater on the convex than on the concave valve. Striae not visible in LM.

Compare

Nupela impexiformis has distinctly capitate apices and lacks a raphe on one valve. Nupela paludigena has more linear valves and narrow axial area. Nupela tenuicephala has more linear valves and capitate ends.